1. Field of the Invention
This invention relates to a joiner for vertical joint which is designed to be placed at a vertical joint formed between end faces (or side faces) of neighboring external wall members such as siding boards.
2. Description of the Related Arts
It is known to construct the external wall of building by attaching external wall members such as ceramic siding boards to the framework of building in such a manner that the end portions (or end faces) of external wall members are butted against one another. FIG. 6 illustrates one example of such an external wall structure, wherein the coupling of external wall members 10 are joined together in such a manner that the end faces of external wall members 10 are butted against one another by making use of a couple of fastening members 12 secured to a vertical furring strip 11. In this case, by taking the expansion and shrinkage of the external wall members 10 due to temperature or the dimensional shrinkage with time into consideration, a couple of neighboring wall members are usually fixed to the furring strip 11 in such a manner that a gap (vertical joint portion) 13 of about 10 mm is provided between the facing ends of these neighboring wall members. An elongated vertical joiner 20 is used to keep space between the facing ends.
The elongated vertical joiner 20 for vertical joint provided with a raised portion 21 is attached to the vertical furring strip 11 in such a manner that the raised portion 21 can be fitted into the gap or vertical joint portion 13. By the way, the vertical joiner 20 shown in FIG. 6 is of a type called a hat joiner and usually made of resin or metal. The worked structure of the vertical joint portion where the aforementioned vertical joiner 20 is employed is also applied to the joining gap portions on both sides of the external corner formative member 30 as shown in FIG. 7 (by the way, in FIG. 7, the same reference numbers as those of FIG. 6 are employed for the constituent members having the same functions as those of FIG. 6).
A sealing compound 14 made of an elastic material is filled in the gap 13 in order to prevent rain water from penetrating inward through this gap 13. The raised portion 21 of the elongated vertical joiner 20 functions as a receiving area for the sealing compound 14. As for specific examples of the sealing compound 14, modified silicone, polysulfide, polyurethane, acrylic and butyl rubber are frequently employed due to their characteristics of elastic deformation, enabling them to elastically deform, to absorb or to follow any changes in the gap (width of joint) resulting from the shrinkage or expansion of the siding boards after the installation thereof, thereby preventing the fracturing of the hermetically sealed state of the gap that may be caused due to the cracking or peeling of the sealing compound 14.
By the way, if the sealing material for sealing the vertical joint portion is filled in the vertical joint portion under such a condition that only a couple of end faces of siding boards disposed on the opposite sides of the sealing material (bonding interfaces) are kept in a bonded state with the other aides of the sealing material being kept in a non-adhered state (kept free), the sealing material is enabled to exhibit an excellent follow-up property relative to the shrinkage and expansion of the siding boards. However, as shown in FIG. 8 illustrating the top view of the worked structure of the vertical joint portion, according to the worked structure of the vertical joint portion where the aforementioned vertical joiner 20 is employed, the surface region of raised portion 21 of the vertical joiner 20 (bottom face of the joint) becomes a third bonding Interface in addition to the aforementioned couple of end faces of siding boards disposed on the opposite sides of the sealing material. As a result, the elastic deformation of the sealing material is restricted by this third bonding interface, thereby obstructing the follow-up property of the sealing material and hence possibly leading to problems such as the cracking or peeling of the sealing member as the siding boards are shrunk or expanded. If the cracking or peeling of the sealing member is generated, the hermetical property of the sealing member in destroyed. Therefore, the cracking or peeling of the sealing member should be prevented at all costs.
In view of overcoming this problem, there has been proposed to adhere a tape called a bond breaker which is poor in adhesivity to the sealing material onto the surface region of the raised portion 21 of the vertical joiner 21. As for the specific examples of this bond breaker, there have been proposed various kinds of materials such as a water-repellent tape made of paper or cloth having a water-repellent treatment surface (Japanese Utility Model Unexamined Publication S62-22248), a release paper (Japanese Utility Model unexamined Publication H4-134306), a resin tape which is surface-treated so as to minimize the surface roughness and to make the surface thereof lustrous and smooth (Japanese Patent Unexamined Publication H11-36553), etc.
However, the conventional bond breakers are all defective in that the releasability thereof to the sealing material is not necessarily sufficient, so that they are still incapable of completely avoiding the formation of aforementioned third bonding interface between the surface region of raised portion of the joiner for vertical joint and the sealing material. As a result, there are occasionally occurred situations where the cracking or peeling is generated in the sealing material that has been filled in the vertical joint.
This invention has been accomplished under the circumstances as mentioned above, and therefore, an object of the present invention is to provide a joiner for vertical joint, which is very low in adhesiveness to a sealing material to be employed on the occasion of fixing the ordinary external building boards or siding boards, thereby making it possible to almost completely prevent the sealing material filled in the vertical joint from being subsequently cracked or peeled.
With a view to realize the aforementioned object, the prevent inventor has made a large number of experiments on the adhesiveness or releasability between various kinds of the sealing materials and various kinds of material to be employed as a joiner for vertical joint or as a bond breaker. The results of these experiments are shown in Table 1.
Namely, Table 1 shows the results wherein the feeling of releasability of the sealing materials from the joiners is evaluated at the moment when the sealing material is picked up and pulled by one""s fingers. In this test, each of the sealing materials of various manufactures was cured for three days after it was applied to each of the bond breakers of various manufacturers, which was adhered in advance onto the top surface (bottom face of the joint) of hat joiner disposed at the interconnecting gap between the neighboring right and left siding boards. In Table 1, a sample wherein the sealing material was enabled to be completely peeled away from the joiner is indicated by a mark O; a sample wherein the sealing material was enabled to be partially peeled away from the joiner is indicated by a mark xcex94; and a sample wherein the sealing material was completely adhered onto the joiner is indicated by a mark x. The symbols A, B, C, D, E, F, G, H, a, b, c, d and e shown in Table 1 represent manufacturers of the bond breakers or sealing materials.
The present invention is based on the findings obtained from the above experiments, and the joiner for vertical joint according to the present invention is featured in that it is adapted to be placed at a vertical joint formed between end faces of a couple of neighboring external wall members, wherein said joiner has a raised portion having almost the same width as that of vertical joint, and at least the top surface region of said raised portion is constituted by a resin layer formed of a resin selected from the group consisting of polyethylene, polypropylene and fluororesin, and having an embossed surface.
In a preferable embodiment of the present invention, the ratio of recessed portions on the embossed surface of the resin layer should be in the range of 10 to 90% per square centimeter, more preferably in the range of 20 to 80% per square centimeter. It has been found as a result of experiments conducted by the present inventor that if the ratio of recessed portions was less than 10% per square centimeter or higher than 90% per square centimeter, the releasability of the sealing material became slightly poor. Whereas when the ratio of recessed portions was confined within the range of 20 to 80% per square centimeter, the affect of embossed surface to improve the releasability of the sealing material was prominently admitted.
By the way, the terms xe2x80x9cembossed surfacexe2x80x9d in the present invention is generally referred to a state wherein recessed portions are formed on a substantially flat surface irrespective of the configuration of the recessed portions. Namely, the configuration of the recessed portions may be optionally selected, e.g. dot-like, stripe-like, etc.
The joiner for vertical joint according to the present invention can be manufactured as follows. Namely, the main body portion and the resin layer portion having the aforementioned embossed surface are separately manufactured at first, and then, the resin layer portion is laminated on the surface region of raised portion of the main body portion of vertical joiner, thereby accomplishing the joiner. Alternatively, the joiner for vertical joint may be entirely molded out of polyethylene resin, polypropylene resin or fluororesin, thus forming it as an integral molded product.
In the case of the former manufacturing method, the raw material for the main body portion may be optionally selected, i.e. any kind of metallic materials or plastic materials can be employed. As for the resin layer portion having an embossed surface, it should be prepared in advance as an adhesive tape, thereby enabling the adhesive tape to be adhered, as required, onto the surface region of raised portion of the main body portion of vertical joiner. According to this former method, the manufacture of the joiner for vertical joint of the present invention cam be extremely facilitated.
The latter manufacturing method is preferable in the respect that since the joiner can be entirely molded by means of extrusion molding method, it becomes possible to obtain a molded product exhibiting an excellent releasability due to the higher density of resin. By the way, in this case, an embossing work is applied by any suitable means to the surface of raised portion of resin joiner after the extrusion molding thereof.
In either manufacturing methods, the cross-sectional configuration of the joiner for vertical joint according to the present invention can be optionally selected as long as it is provided at least with a raised portion which is capable of fitted into a vertical joint to be formed between neighboring external wall members such as siding boards.
According to the joiner for vertical joint of the present invention, since the adhesive force between the sealing material and the surface region of raised portion of the joiner can be extremely minimized, and hence the releasability of the sealing material can be extremely enhanced, there is little possibility that such a third adhesive surface that may restrict the elastic deformation of the sealing material fitted in the joint is formed between the sealing material and the surface region of raised portion of the joiner. As a result, it is now possible to almost completely prevent the sealing material filled in the vertical joint from being subsequently cracked or peeled away.